Cardiopulmonary bypass in the cat

OBJECTIVE: To assess the physiologic response to, and acute survival of, cats undergoing cardiopulmonary bypass (CPB) and to evaluate the efficacy of a commercial human pediatric oxygenator system on cats weighing less than 6 kg. STUDY DESIGN: Experimental study. ANIMALS: Six intact male cats METHODS: Cats were placed on cardiopulmonary bypass by cannulating the cranial and caudal vena cavae and the carotid artery. The pediatric CPB circuit was primed with 150 mL of a balanced crystalloid solution. Venous drainage was enhanced by a controlled, vacuum-assist system. A cross-clamp was placed on the ascending aorta and cardiac arrest was induced by antegrade infusion of a cold cardioplegia solution. After 45 minutes of arrest time, the cross-clamp was removed and the cats were weaned off bypass and decannulated. No blood products were administered. Heart rate, mean arterial pressure (MAP), central venous pressure, arterial blood gas, hematocrit (HCT), total plasma protein concentration (TP), serum electrolyte concentrations, and activated clotting time (ACT) were measured at baseline period (BL), during CPB, 60 minutes after CPB (CPB 60) and 90 minutes after CPB (CPB 90). A complete blood count (CBC), blood chemistry profile, and urinalysis were performed at BL, during CPB, and CPB 90. Cats were euthanatized after CPB 90. RESULTS: Cardiopulmonary bypass resulted in a significant (P <.05) decrease in mean HCT (18.0%) and TP (2.3 gm/dL) at CPB 90 when compared to BL (30.5% and 6.0 gm/dL, respectively). The MAP at CPB 90 (54 mm Hg) was decreased from BL (94 mm Hg). The ACT increased from a mean of 124 seconds to > 400 seconds with heparinization and was reversed to 300 seconds with protamine. Mean platelet counts decreased from BL (369,000 /microL) to CPB 90 (94,500 /microL). Mean white blood cell counts decreased from 13,200 /microL at BL to 2,200 /microL at CPB 90. Upon reperfusion, 1 cat fibrillated but was successfully defibrillated. CONCLUSIONS: Cardiopulmonary bypass was performed successfully in 6 cats weighing less than 6 kg. Acute survival to 90 minutes after CPB was achieved in all 6 cats CLINICAL RELEVANCE: The ability to perform CPB in the cat may allow intracardiac repair of various heart defects in this species.     

Altered expression of G proteins in thyroid gland adenomas obtained from hyperthyroid cats

OBJECTIVE: To determine whether expression of G proteins (G(i) and G(s)) is altered in thyroid gland adenomas obtained from hyperthyroid cats. SAMPLE POPULATION: Adenomatous thyroid glands obtained from 8 hyperthyroid cats and thyroid glands obtained from 4 age-matched euthyroid cats. PROCEDURE: Expression of G(i) and G(s) was quantified in enriched membrane preparations of thyroid gland tissue, using immunoblotting with G(i) and G(s) antibodies and toxin-catalyzed ADP-ribosylation. RESULTS: Expression of G(i) was significantly reduced in thyroid gland adenomas from hyperthyroid cats, compared with normal thyroid gland tissue from euthyroid cats. Expression of G(s) was similar between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE: A decrease in expression of G in adenomatous thyroid glands of cats may reduce the negative inhibition of the cAMP cascade in thyroid cells, leading to autonomous growth and hypersecretion of thyroxine. Understanding the molecular mechanisms for hyperthyroidism in cats may lead to better treatment or, ultimately, prevention of the disease.     

Fungal flora on cutaneous and mucosal surfaces of cats infected with feline immunodeficiency virus or feline leukemia virus

OBJECTIVE: To compare cutaneous and mucosal mycoflora in cats infected with FIV or FeLV with that in noninfected cats. ANIMALS: 85 client-owned cats; 24 seropositive for FIV, 10 seropositive for FeLV, 1 seropositive for both viruses, and 50 seronegative for both viruses. PROCEDURE: Cutaneous specimens were obtained from the coat and external acoustic meatus (ear canal) and mucosal specimens from the oropharynx and rectum. Fungi were isolated from specimens, using Sabouraud dextrose agar incubated at 27 or 37 C for cutaneous and mucosal specimens, respectively. RESULTS: Fungal colonies were cultured from at least 1 specimen from 83 of 85 (97.6%) cats. The most common fungal isolates were Aspergillus spp (cultured from 59.3% of all specimens), Penicillium spp (50.0%), Cladosporium spp (44.2%), Scopulariopsis spp (41.8%), and lipophilic yeasts of the genus Malassezia (31.4%). A greater diversity of fungal genera was isolated from retrovirus-infected cats, and Malassezia spp were more commonly recovered from these cats, compared with noninfected cats. Candida albicans, Cryptococcus neoformans, and dermatophytes (eg, Microsporum canis) were rarely isolated from any cat. Significant differences in frequency of isolation of C. neoformans and dermatophytes were not found between infected and noninfected cats. CONCLUSIONS AND CLINICAL RELEVANCE: Cats infected with FIV or FeLV may have a greater diversity of cutaneous and mucosal mycoflora than noninfected cats. However, infected cats may be no more likely than noninfected cats to expose humans to zoonotic fungi such as C. albicans, C. neoformans, and M. canis.     

Esophageal obstruction caused by a left aortic arch and an anomalous right patent ductus arteriosus in two German Shepherd littermates

OBJECTIVE: To present details of surgical management of an unusual vascular ring anomaly in two German Shepherd littermates. STUDY DESIGN: Clinical case report. STUDY POPULATION: Three-month-old intact male and female German Shepherd littermates. RESULTS: In each dog, the esophagus was obstructed by a vascular ring comprised of the left aortic arch, an anomalous patent right ductus arteriosus, and the pulmonary artery ventrally. Surgical treatment consisted of dividing and oversewing the patent right ductus arteriosus. Neither dog has clinical signs of esophageal disease one year after treatment. CONCLUSION AND CLINICAL RELEVANCE: This vascular ring anomaly should be considered a possibility in any young dog with esophageal obstruction and a machinery murmur.     

Plasma pharmacokinetics of selamectin after a single topical administration in the American bullfrog (Rana catesbeiana).

Parasitism is common in wild and captive amphibians; however, pharmacologic data are lacking for anthelmintic drugs. This study was developed to determine the plasma pharmacokinetics of selamectin after topical administration in bullfrogs. Thirty-two adult American bullfrogs (Rana catesbeiana) were randomly assigned into eight groups of four with each group representing a different collection time point. Seven groups received selamectin (6 mg/ kg) topically and the remaining group served as the untreated control group. One group of frogs was euthanized and blood samples immediately collected on days 0 (control), 1, 5, 10, 15, 20, 25, and 30. Plasma was analyzed for selamectin using high performance liquid chromatography with fluorescence detection. Individual samples were analyzed, then data were reported as the mean of the four frogs at each time point. A histologic evaluation of the lung, liver, kidney, and skin tissues was performed and none of the frogs showed histologic evidence of toxicity due to selamectin administration. The mean peak plasma concentration was 162.5 +/- 42.3 ng/ml, area under the curve was 2,856 ng day/ml, mean residence time was 12.2 days, and disappearance half-life was 1.87 days. Based on the plasma pharmacokinetics, bullfrogs appear to absorb selamectin very efficiently, concentrations reach high levels in the plasma, and there were no apparent histologic effects from single dose administration.     

接种沙门氏菌苗可使新生雏鸡和强制换羽母鸡得到免疫保护

过去人们常认为,由于刚出壳雏鸡的免疫系统尚未发育成熟,同时肠道内缺乏有益的微生物,因而处于高度的敏感期,此时接种沙门氏菌苗产生的保护作用很有限。然而,最新的研究表明,在这些敏感期接种疫苗,可诱发产生保护作用。